Hydrogen has a reputation as a clean source of energy, especially when compared to fossil fuels such as oil and coal. But there's just one problem: You need to burn methane, itself a fossil fuel, to make hydrogen. So with current technology, hydrogen isn't as clean as its reputation.
Add to that, current technology is expensive because to isolate hydrogen you must create electrolysis reactions, which separates hydrogen atoms from oxygen atoms in water. Again, with current technology, you need expensive platinum as a catalyst for that process.
So hydrogen fuel isn't that clean and isn't that inexpensive – yet. But a team of researchers led by Tewodros (Teddy) Asefa, an associate professor of chemical and biochemical engineering at the Rutgers School of Engineering, says it's solved that problem.
In a paper published in Angewandte Chemie [Applied Chemistry] International Edition, Asefa and his colleagues report that they based their new catalyst not on platinum, but on inexpensive nanotubes, sheets of carbon one atom thick that are rolled into pipes 10,000 times thinner than a human hair.
And instead of relying on methane, hydrogen could be produced by electricity generated by such renewable sources as wind and solar energy, or even by nuclear energy.
Further, they say, the nanotube process is so efficient and today's emission controls are so effective that cars and even power plants could even use methane in the process and operate far more cleanly than they would using oil or coal.
The new technology is called "noble metal-free, nitrogen-rich carbon nanotubes." Asefa's team reports that the tubes function properly in any environment, whether basic, neutral or acidic, increasing their options for coupling with the most efficient oxygen-evolving catalysts that are important in separating oxygen and hydrogen atoms from water.
Further, they say, these nanotubes react catalytically with the hydrogen with nearly the efficiency of platinum. This would be analogous to the difference between two cooking vessels, one made of copper – an excellent but expensive heat conductor – and the other made of aluminum – nearly as good a conductor and much less costly.
There are several benefits of relying on hydrogen for energy. Among them is that it generates no air pollutants, especially if it is created without burning methane. Another reason is that it is plentiful: The United States produces 100 billion cubic feet of hydrogen each year, enough to power as many as 11,000 homes, according to the American Gas Association.
"Hydrogen has long been expected to play a vital role in our future energy landscapes by mitigating, if not completely eliminating, our reliance on fossil fuels," Asefa says. "We have developed a sustainable chemical catalyst that, we hope with the right industry partner, can bring this vision to life."
In fact, Asefa and his colleagues already have filed for a patent on their technology.